1. Field of the Invention
This invention relates to electronics packaging systems in general; and, in particular, to systems for packaging electronic circuitry for instruments, e.g. measurements-while-drilling tools, which are subjected during operation to a harsh environment such as severe vibration and impact shocks, and high bending and torsional stresses.
2. Description of the Prior Art
With the ongoing technological advances in the art of drilling boreholes in the earth, typically oil and gas wells, more and more electronics has been used in downhole environments. The technology of measurements-while-drilling (MWD) has developed whereby measurements concerning the condition of the well are performed downhole while the well is being drilled. Electronic measuring tools are placed in series with the drilling string in proximity to the drilling bit.
The drilling environment of a drilling bit boring into earth formations is extremely hostile. The rotational forces of the bit being rotated at the end of a long string of drilling pipe driven by rotation from the surface have created reliability problems for downhole electronics in the measuring tools. Many of these problems have resulted from the shortcomings of the conventional technology available for packaging the electrical components.
In particular, the extremely high vibration set up in the drilling bit and collars above the bit, as well as the sudden impact shocks caused by the drilling process, have frequently caused prior art electronic instruments in proximity to the bit to fail. The electronic equipment that is used while drilling must be reliable enough to continue working during the lifetime of a drilling bit. Operators and drilling contractors find it unacceptable from a time delay and cost standpoint to interrupt drilling to replace electronic equipment.